from itertools import combinations

N = int(input())

P = [0] * N

D = [[float('inf')] * N for _ in range(N)]

for i in range(N):
    D[i][i] = 0

for _ in range(N-1):
    v, u = map(int, input().split())
    D[v-1][u-1] = D[u-1][v-1] = 1
    P[v-1] += 1
    P[u-1] += 1
    
for k in range(N):
    for i in range(N):
        for j in range(N):
            D[i][j] = min(D[i][j], D[i][k] + D[k][j])

val = 0
for i, j in combinations([k for k, v in enumerate(P) if v == 1], 2):
    if val == 0:
        val = D[i][j]
    elif val != D[i][j]:
        print('No')
        break
else:
    print('Yes')